The present invention relates to a mount for mounting a cab on a vehicle frame, having a first and a second mount part, one of these being provided on the cab, and the other being provided on the vehicle frame, and having a vibration damper acting between the frame and the cab. The first mount part includes an inner anchoring part and an outer anchoring part that is movable with respect to the inner anchoring part, the outer anchoring part radially enclosing the inner anchoring part, and an elastic spring element acting between the inner and the outer anchoring parts.
A mount for mounting a cab on a vehicle frame is described, for example, in International Published Patent Application No. WO 97/08038. The mount includes a rubber bearing provided between the frame and the cab, the radially external part of the rubber mount being joined to the cab by a plurality of bolts, and the radially internal part of the rubber mount being joined to the frame by a bolt. A shock absorber and a spring acting in parallel thereto are disposed between the rubber mount and the vehicle frame. The mount is not designed in a manner allowing it to be detached using simple means, e.g., by raising the cab, in order to facilitate service and maintenance measures. In addition, the mount has the disadvantage of its manufacture and assembly being costly due to a complex design, which includes a rubber member, a separate spring, as well as a separate shock absorber.
It is an object of the present invention to provide a mount that facilitates the performance of service measures and that may be manufactured inexpensively and assembled easily.
The above and other beneficial objects of the present invention are achieved by providing a mount with which the cab may be raised relatively to the frame, e.g., in a swivelling manner, from a driving position into a service position and may be lowered from the service position into the driving position. The first and second mount parts are separated from each other in response to raising the cab into the service position and are joined again in response to lowering the cab into the driving position. In the driving position, the first mount part is positioned in a receptacle formed on the inner anchoring part. A centering device is provided, which aligns the first mount part with respect to the second mount part in response to the cab being lowered into the driving position.
The arrangement according to the present invention attains an especially high degree of serviceability, in that the cab, e.g., of a truck, may be raised relatively to the vehicle frame, into a service position. Two first mount parts may be positioned to the left and right of the longitudinal vehicle axis, between the cab and the frame. The cab may be moved about a pivot located in its front region, from the driving position into the raised service position. In addition, the arrangement according to the present invention allows a particularly compact method of construction, since the first mount part unites a plurality of functions, for which several separate component parts were necessary in the conventional mount.
A particularly sturdy arrangement is achieved by forming the first mount part as a lug, at least a section of which may be accommodated in the receptacle.
A particularly simple arrangement is achieved, in that the centering device includes a first guide surface formed on the first mount part and a second guide surface, which is formed on the receptacle and interacts with this first guide surface.
A further aspect of the present invention provides for the first and/or the second guide surface being inclined so that the first mount part is centered upon being inserted into the receptacle.
The mount may be manufactured in a particularly inexpensive manner, when the inner anchoring part is in the form of a ring, the annular opening of which forms the receptacle.
A particularly simple and compact method of construction may be achieved, in that at least a section of the ring includes a diameter that decreases, e.g., in a conical manner, in the insertion direction of the first mount part.
Undesired play between the cab and the vehicle frame may be prevented by providing a section on the side of the ring facing the cab, the section being radially enlarged in the external direction and forming a seat for a supporting body.
A locking mechanism may be provided, which secures the cab in the driving position.
A particularly stable manner of locking is achieved in that the locking mechanism includes a locking element that grips the segment radially enlarged in the external direction, from behind.
Another advantageous manner of locking consists in the locking mechanism having a locking element, which acts between the second mount part and the inner anchoring part.
An additional improvement may be attained by providing a section on the side of the ring opposite to the cab, the section being radially enlarged in the external direction and defining, together with the outer anchoring part, a break-away prevention mechanism. This prevents the cab from moving excessively with respect to the vehicle frame, even in response to the elastic spring element failing, e.g., as a result of an accident.
An improvement in the vibration isolation of the cab is achieved by providing a hydraulic shock absorber that acts between the first and second mount parts.
For hydraulic damping, a further aspect of the present invention provides a first chamber filled with hydraulic fluid and a second chamber, which is separated from the first chamber, and is in fluid communication with the first chamber via a duct. The volume of the first chamber is changed in response to a relative movement of the first and second mount parts so that hydraulic fluid is moved in the duct between the first and second chambers. Such an arrangement may reduce occurring vibrations.
A particularly compact design is attained by arranging the first chamber and/or the second chamber between the inner and the outer anchoring parts.
At least a section of the first chamber may be bounded by the elastic spring element.
The duct may be formed by a gap bounded by the inner anchoring part and the outer anchoring part.
To form the gap, the outer anchoring part may include a choke or throttle element, which extends around the inner anchoring part.
Elasticity may be attained in the transverse direction, in that the throttle element is made of elastic material and is especially formed in one piece with the elastic spring element. The one-piece design of the elastomeric spring element and throttle element may reduce the manufacturing costs further.
Improved vibration isolation may be achieved, in that the throttle element includes a substantially cylindrical section pointing toward the second chamber, the bottom surface of the cylindrical section having an opening therein which, together with the inner anchoring part, forms the gap.